I drove the van again this evening and I could not hear the noise. I looked
under the van, check the CV bolts, jacked up the rear, shook the tires,
shook the axles, etc. nothing.  There is a large consensus that it could be
the CV joints. Since the noise goes away when I step on the clutch could
that still be the problem? Aren't they still turning whether the clutch is
in or out? Also, since the noise is the same "tempo" whether I'm in 3rd or
4th gear I guess I can take the engine having problems out of the equation?

Thanks,
Bryan